of san francisco



@uiten-giant @nicht @ff-ire.

Leiters Patent No. 80,928, dated August 11, 1868.

IMPROVEMENT Ill'V LATHE-GHUCK.

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Be it known that I, J. S.V DETnIGK, of San Francisco, in the county of San Fran ciscc,.and State of California, have invented a new. and vimproved Chuck; and I do hereby declare4 thatV thefollowing is a full, clear, andexact descriptionthereof,whieh will enable those skilled in the art to make and use the same, reference being had to the accompanying drawings, forming part of this specification, i

This invention hasv for its -object to provide a chuck, for use on lathes in machine-shops, and "for other purposes, which shall enable the operator to move the centre of his'work without removing the chuck from thc lathe.

And itconsists in attaching the chuck to a back plate, upon whichit is made to slide with the work which it'contains, as will'be hereinafter described. i

Figure 1 represents a front view ofthe chuck, attached to the back plate.

Figure 2 is a section' of g. 1, through the line x z.

Similar letters of reference indicate corresponding parts. n

The chuck is formed in the manner usual in making the simple dog-chuck.

The dogs are operated by screws, the ends of which pass through the periphery of the chuck, with collars, which prevent longitudinal motion in the screw,'but allow the screw to turn freely, the nut for lthe screw bein in the dog. i

The dogs travel irl-grooves, which radiate from the centre of the plate,' as seen in fig. 1, and they are held to their places by plates, which lap onto projecting iiang'es on each side.

The screws, by which they are adjusted and moved from or to the centre, pass directly through them, as seen in the drawing. i i

A is the chuck-plate.

B represents the dogs, between which the work to be bored, or turned, or held, is secured.

C represents the screws, by whichthe dogs are operated. l

D is the back plate, to which the chuck is attached by a dove-'tail sliding connection.

I This plate hasahub, E, on its back side, which screws on to the mandrel of the lathe.

The dove-tail on' the inner side of this plate (which receives a correspondingdovetail on the hack 0f the chuck) ishollow, so las to receive the screw Gr, hy which the chuck is operated, and also a lug on the back of the chuck-plate, through which the screw passes, so that, by turning this screw, the chuck is moved on the plate D (in a direction parallel with the screw) either way from the centre;

` The arrangement isthe same as for moving` the dogs, there being collars on the wrench-end of the screw, to prevent longitudinal motion. l

G is the screw by which the4 dh'uek is moved on the plate D. A p

It will thus be seen that a piece ci' work may be securely fastened in the chuck, and moved from the centre for boring or turning-and which, for particular kinds of work, will cause a greatsaving of time, and be at once appreciated by al1 who are conversant in machine work. p y i e The chuck will be found useful for wood, as well as for work in metals, and may be applied'toeither purpose with great advantage. i

Having thus described my invention, I claim as new, and desire tosecure by Letters Patentlhe back plate D, constructed as described, in combination with the sliding chuck and adjusting-screw C, all Asubstantially as setfor'th. f v

The above specification of my invention signed by me, this thirtieth day of'November, 1867.

J, s. Darmon.

Witnesses:

Jos. PERKINS, S. W. IIOYT. 

